Conventional adjustable wrenches generally include a stationary jaw integrally formed with a wrench body, an adjustable jaw that slides towards or away from the stationary jaw to span a space, and a knurl that when rotated moves the adjustable jaw to selectively narrow or widen the space for engaging various sizes of nuts and bolts. The adjustable jaw includes a plurality of teeth that mate with the knurl to create a worm gear drive that moves the adjustable jaw.
A perennial problem associated with adjustable wrenches is that the adjustable jaw of the wrench frequently slips during use and between uses. The adjustable jaw often slips when the adjustable wrench is rotated or twisted to loosen or tighten a nut or bolt. A related problem is that the knurl becomes loose and rotates slightly, causing the adjustable jaw to move and disengage the nut or bolt, thereby causing the nut or bolt to strip or become rounded. Thus, a user must constantly adjust the adjustable jaw of the wrench to maintain a secure hold on the nut or bolt. In some situations, pressure is constantly applied to the knurl by a user's thumb or finger so that the adjustable jaw does not slideably move outward. Many applications require the use of an adjustable wrench in areas where the nuts or bolts are not directly or easily accessible, making it difficult and inconvenient to constantly make the necessary adjustments.
Various known adjustable wrenches include braking mechanisms that prevent a knurl from rotating, thus restricting the movement of the adjustable jaw. These wrenches, however, include numerous intricate parts that must be machined to exact tolerances, which increases the retail, manufacturing, and production costs. Such wrenches also generally require a sequence of coordinated motions and the use of an additional tool for maneuvering the braking mechanism, making it difficult when attempting to access tight areas. In addition, many adjustable wrenches that include braking mechanisms do not include a means for locking the braking mechanism so as to restrict the slippage of the braking mechanism.
Accordingly, there remains in the art a need for an adjustable wrench that provides an adjustable braking mechanism for locking an adjustable jaw in a fixed position, where the adjustable wrench is inexpensive and easy to manufacture. There is also a need for an adjustable wrench that includes a locking mechanism for selectively locking the braking mechanism in place, thereby restricting the braking mechanism from moving and as a result, preventing the adjustable jaw from sliding.